If I'm not mistaken, the series "Kumo Desu ga, Nani ka?" has the official English title, "So I'm a Spider, So What?" Can we create the tag so-im-a-spider-so-what and make kumo-desu-ga-nani-ka its synonym? I think this would be in line with the current policy on tagging.
As for "nani ka" or "nanika", "ka" is a Japanese particle (just like "ga") and usually stands alone. However, "nanika" is also a single expression, meaning "(so) what (are you trying to say)?". Since there are far more results for "nani ka" (with space), I decided to use the current tag as-is. (Not that I think it will affect so much though...)